Story time

River facts

Hi kids! Welcome to my river facts photo gallery. Some of my friends at the St. Johns River Water Management District took these cool pictures of my river. Enjoy the slide show!

The St. Johns River is the longest river in Florida – 310 miles. It is one of the few rivers in the United States that flows north.

The land area that drains into a water body is called a drainage basin, or watershed. The St. Johns River is divided into three drainage basins.

Because the river flows north, the upper basin is the area to the south that forms its marshy headwaters in Indian River and Brevard counties.

The middle basin of the St. Johns River is the area in central Florida where the river widens, forming lakes Harney, Jesup, Monroe and George.

The lower basin of the St. Johns River is the area in northeast Florida from Putnam County to the river's mouth in Duval County, where the river empties into the Atlantic Ocean.

The width of the river varies. It is a flat marsh at its headwaters and averages about 2 miles in width betwen Palatka and Jacksonville. It widens to form large lakes in central Florida.

The total drop of the river from its source in marshes south of Melbourne to its mouth in the Atlantic near Jacksonville is less than 30 feet, or about one inch per mile, making it one of the laziest rivers in the world.

Because the river flows slowly, it is difficult for the river current to flush pollutants.

Major pollution sources include discharges from wastewater treatment plants and stormwater runoff from urban and agricultural areas. This runoff carries pesticides, fertilizers and other pollutants into canals, ditches and streams that lead to the river. River pollution is concentrated around urban areas.

Salt water enters the river at its mouth in Jacksonville. In periods of low water, tides may cause a reverse flow as far south as Lake Monroe – 161 miles upstream from the river's mouth

Major tributaries and smaller streams and rivers that flow into the St. Johns River include the Wekiva River, the Econlockhatchee River and the Ocklawaha River.